Enzymatic Browning in Basilicum Based Pesto

  This week’s class experience was one we had been eagerly waiting for, pasta and pesto making. Considering very few of us had ever enjoyed the delicacy of fresh made pasta, this class was a treat. Combined with our class-made basil pesto, this pasta lesson was a big hit.  Before we began our pasta and pesto making, we learned about how to prevent browning in our pesto, something that occurs from a process called enzymatic browning. The following text will discuss the process of enzymatic browning, specifically, in basil pesto.

  To understand enzymatic browning, we must first understand what an enzyme is. An enzyme is a “a specific type of protein,” made unique by its long, complex formation. (Food Crumbles, p. 1, 2016) They are comprised of long chains of amino acids, which “will then curl up in a complex 3D structure.”  (Food Crumbles, p. 1, 2016) Though enzymes are such large, complex structures, they always carry an empty space within them. This space is where the enzyme can house a foreign molecule and use it to aid in its chemical reactions. When an enzyme pairs with a molecule, it can act as a catalyst in many different chemical reactions. For the purpose of this assignment, we will be discussing enzymes as a catalyst in the process of browning.

  The basilicum, or, basil leaves that are used in pesto are high in an enzyme called polyphenol oxidase, often abbreviated as PPO. When given the right conditions, “...this enzyme catalyzes the browning of a lot of fruits and vegetables.” (Food Crumbles, p. 1, 2016) The browning occurs because the enzyme PPO catalyses “a reaction in which polyphenols are formed, these polyphenols have red/brown to black colours.” (Food Crumbles, p. 1, 2016) This unwanted browning reaction most likely occurs from irregular temperature or PH, such as leaving pesto without refrigeration or acidity. To prevent pesto or any other plant containing PPO from browning, one could reduce the temperature environment or lower the PH levels. This could be done by refrigeration or adding an acidic substance, such as lemon juice, to the food. Lower temperature and lower PH inhibits enzymes from catalyzing their reactions, and therefore inhibits browning of the produce.

References

Enzymes in food-The basics & pesto. (2016). Food Crumbles. Retrieved from

   https://foodcrumbles.com/enzymes-in-food-the-basics/